Arc-lamp electrode.



G. M. LITTLE. ARC LAMP ELECTRODE. APPLICATION FILED SEPT.3,1907.

Patented Aug. 17, 1909.

ATTORNEY UNITED srArEs PATENT orator.

GEORGE M. LITTLE, OF PITTSBURG', PENNSYLVANIA, ASSIGNOR' TO" WESTINGHOUSE ELEC- TRIC & MANUFACTURING COMPANY, A CORPORATION OF' PENNSYLVANIA.

ARC-DAMP EW'IRODE.

Specification of Letters-Patent.

Patentedfkug. 1-7], 1909.

PPHORQM fil d ent nce: 1 19117-- Serial-m1. 1,2 9

of Pittsburg, inthe countyof. Allegheny, andf State of Pennsylvania, have'invented a. new and useful Improvement in Arc-Lamp. Else 7 trodes, ofwhich'the-following is a, specification;

My. invention relates-to electrodes for arelamps and particularly-to suchelectrodes as are adapted for .usewith; other electrodescontaining a material which is a conductor when fused, such, for example, as a mixture of magnetic oirid of iron and oxids of titanium and chromium.

The object of my' invention. is to; provide an electrode of the character indicated, for use in lamps supplied from alternating current circuits, that shall be substantially nonconsumable and that shall render the are more luminous and steady than electrodes heretofore provided.

In another application Serial No. 316,132, filed by me May 10, 1906, I have'diselosed an arc lamp having a metallic lower electrode and a composition upper electrode containing the magneticoxid of iron and the oxids of titanium and chromium. In the operation of the lamp, set forth in said application, a pool of fused slag containing the said oxids forms upon the end of the composition electrodes, and, when the electrodes are brought together by the operation of the feeding mechanism, some of the fused slag is transferred to the lower metallic electrode. Some-of the fumes or volatile oxids that are given off at the are also deposit upon the metallic electrode and become fused into a slag. The are thereafter plays between the pool of slag upon the end of the composition electrode and the slag that has been transferred to, or has been deposited upon, the metallic electrode. Since the arc thus produced is usually superior in luminosity and steadiness to the are produced directly between the metallic electrode and the composition electrode, the presence of the slag upon the metallic electrode is highly important to the most successful operation of the lamp. In order to cause the slag upon the lower metallic electrode to attain such a degree of fluidity that it will spread over the entire end of the electrode and become so fastened thereto that it will "not craok loose,,I have heretofore-provided a slender, substantially heat insulating; sup! port for the metallic eleetnodeof: suclhchar actenthat; the heat. produced by,- the arc will; be' but slowly: conducted. away from: the lectrode.. connection with; direc current circuits 8.

has been found; highl satisfactory, butv it is entirelyunsuitable; or use in alternating cement lamps because.- of the presence of coppera Iron may-be employedl alonmifi de sired, but, because of its low fnsin point,,it becomes. very: readily, oxidized an is therefore quite rapidly consumed.

' lb present i1iventriuni plloflidss electthat it is substantially non-consumable, or

In lamps that are employed; in.

lower electrode composed of iron and coppertrode the fusing.-

o hich; is; so high;

is but very slowly consumed, and for which 1 the molten slag obtained from the composition electrode possesses such a positive degree of adhesion that theslag becomes securely fastened to it. The electrode is provided with a slender or heat-insulating support so that the molten slag is caused, by

the intense degree of heat, to spread over the end of the electrode. A material which I have found suitable for use in such an electrode is an alloy of iron and chromium, the fusing point of which is considerably higher than that of the iron alone, and, for that reason, is but very slightly soluble in the molten slag-and is not readily oxidized and consumed. I prefer to employ the material in the granular form in order to reduce the heat conductivity of the electrode and to provide further means for concentrating the heat of the are upon the end of the electrode to assist in causing the slag to spread over it.

In the single figure of the accompanying drawing, which is a view, partially in elevation and partially in section, of an arc lamp that embodies my invention, an upper elec-- trode 1 ,is preferably composed, as hereinbefore described, of the magnetic oxid of iron and the oxids of titanium and chromium, and a lower electrode 2 comprises a cup-shaped receptacle 3 composed of iron or other suitable material, and an alloy. of iron and chromium contained within the receptacle. The alloy is preferably in granular form in order to decrease the heat .conductivity of the electrode, and the receptacle is provided with a slender," substantially 7 heat-insulatin supporting rod 5 that extends upward y into the receptacle."

While I prefer to employ an alloy of iron and chromium, other suitable conducting alloys or materials having high fusing points and for which-the moltenvslag obtained fromthe upper composition electrode during the feeding operation of the lamp possesses such a degree of adhesion that the slag will spread over and become fastened to the lower electrode, may 'beemployed, if

desired.

I claim'as my invent on: 1. In an arc lamp, the combination with an electrode containing a material which is an electrode containing a material which is a conductor when fused, of'another elec-' trode containing an alloy of iron and chromium.

2. In an arc lamp, the combination with a conductor when fused, of another elmtrode containing a granulated alloy of iron and chromium.

3. In an arc lamp, the combination with an electrode containing a material which is a conductor when fused, of another electrode containing a conducting material hav- .ing a hi her fusing point than that of the aforesai electrode and for which the fused material of the aforesaid electrodepossesses a positive degree of adhesion.

4. In an arc'lamp, the combination with an electrode containing a material which is a conductor when fused, of another electrode containing a granulated conducting material having a higher fusing point than that of the aforesaid electrode and. for

subscribed my name this 23rd day of August,

GEORGE M. LITTLE. Witnesses I O'r'ro S. SoHArRER, BIRNEY HINES. 

